水泥混凝土路面脱空的探地雷达图像特征分析

脱空是水泥混凝土路面的常见病害，也是行车安全的主要隐患。探地雷达法通过观测分析高频电磁波反射信号特征来研究探测目标体的性质与规模，可以快速、有效地确定路面脱空的位置与充填情况。GprMax2D模拟结果、雷达实测资料和开挖验证情况的综合分析成果表明，充泥和充气空洞的雷达图像十分相似，特征明显，在空洞正上方都会出现一组非常明显的强反射信号，同相轴呈弧型，由于介电常数的明显差异，使得空洞充泥时反射波与直达波相位相反，而充气时反射波与直达波相位相同；不密实区域同相轴错断，显示出多条不规则弧形曲线。 

Analysis on the image features of ground penetrating radar for cavity of concrete pavement

The cavity is one of the common defects in cement concrete pavement, and it is also the mainly hidden danger for driving safety. Ground penetrating radar can detect the cavity's scale and character by observing and researching the signal features reflected from high-frequency electromagnetic wave. With the advantage of confirming the cavity's existence and scale quickly and effectively, GPR has turned into a valid method in non-deconstruction defecting of road by far. Based on comprehensive analysis among GprMax2D simulating results, radar detecting statistics and verifying on site, the conclusion demonstrates that the radar image between aerated cavity and soil-ballasted cavity is pretty similar with an obvious feature:A group of evident strong reflection signal, arc-shaped axis in the same phase, will occur above the cavity; due to the distinct difference of dielectric constant, the phase between the reflection waves and direct waves is opposite for the soil-ballasted cavity while it is the same for the aerated cavity; the alignment of non dense area is irregular showing several irregular arc curves.